Wellhole inclinometer



Patented Apr. 25, 1939 WELLHOLE INGLINOMETER Harry H. Jones, LosAngeles, Calii'., assignor, by

mcsne assignments, to Technical Oil Tool Corporation, Ltd., Los Angeles,Calif., a corporation of California Application June 5, 1929, Serial No.368,728

Claims.

This invention relates to a method and means for determining theinclination of well holes. It is often of great importance to know theamount by which deep well bores, especially oil wells, depart from thevertical. One method of determining this has been to lowera glasscontainer, partly filled with hydrofluoric acid, in the well by means ofthe sand line, allow it to remain for an interval at a predetermineddepth, and then bring it back. to the surface. The acid etches the glassand as the surface of the acid remains horizontal, the inclination ofthe well at the point where the container was stopped may be readilydetermined. This method has various drawbacks, the principal one beingthat of the time consumed in the special operation of running thecontainer in and out of the hole.

It is a primary object of this invention to provide a means for loweringa container, as just described, to any predetermined depth with greatrapidity without the use of a special line and by which it can bebrought back to the surface when the drill string is withdrawn. Anotherobject is the provision of means whereby the container may be stopped atany desired point in the well, without damage to the container.

A preferred form of my invention is illustrated in the accompanyingdrawing, in which:

Fig. 1 is a diagrammatic axial section of a well much enlarged indiameter; Fig. 2 is an axial section through a portion of the drill pipewith the acid container disposed therein; Fig. 2a is a similar sectionshowing the upper portion of a slightly different form of container;Figs. 3, 4,

35 and 5 are sections as seen on the correspondingly numbered planes ofFig. 2.

Referring with more particularity to the drawing, a well bore 1 isshown,the lower portion of which is considerably inclined from the ver-40 tical. It has the usual casing 8 and string of drill pipe 9, thelatter having couplings I0, tool joints H, and the drilling tool l2 atthe bottom. A cartridge or holder l3, holding the acid container isshown stopped in the receiving member 45 It. The cartridge consists of atube l5, having an intermediate shoulder or collar it of enlargeddiameter, a head I1 with space for the acid container at the upper end,and a conical pilot piece 18 at its lower end. The pilot piece is fluted50 and provided with several ports l9, and the tube has also a number ofports 20. Thus circulation can be maintained at all times from the drillpipe through the cartridge. Head ll has a bore IIa to receive acylindrical glass acid container.

55 22 which is closed with a plug or cork 23. Bore Ila is closed with athreaded plug 24, which should seat on a. gasket to insure tightness.Above and below the container are springs 25 and 26, which serve tofloat the container between the bottom of the bore and the plug and 5thereby isolate it from shocks.

The receiving'member I4 is adapted to be inserted between the pin endIla and the box end D of a tool joint and is usually termed a sub. Itmay be inserted at any tool joint in the string. 10 It has a large bore14a in which is slidably disposed an abutment member or thimble 28adapted to be engaged by collar l6 and arrest the downward travel of thecartridge. Thimble 28 is resiliently supported on a spring 29 and has askirt 30 designed to guide the cartridge and assist in keeping it inalinement with the drill pipe. A number of ports 3| are provided to passthe circulation. Member M has also a smaller bore Mb to guide andaxially aline the cartridge with the drill pipe 9. Recesses 32 areprovided to permit the circulation to pass.

The method of operation is as follows: The drill pipe with the drillingtool at its lower end is run in the hole, a tool joint with thereceiving member It being inserted in the string of drill pipe at thepoint where it is desired to measure the inclination of the hole. Thestring is then rotated and drilling progresses in the usual manner. Whenthe string is to be pulled, because of the drill becoming dull or forany other reason, the Kelly is set back and the cartridge is droppedinto the drill pipe. It falls by gravity until the collar i6 encountersthimble 28 which brings it to a stop. The friction of the cartridgepassing 35 through the mud laden fluid with which the drill pipe is atall times filled serves to reduce the speed of its fall, andparticularly at tool joints, which have a bore substantially less thanthat of the drill pipe. Its downward progress will 40 be indicated by aclicking noise as it passes each tool joint, clearly audible on thederrick floor, and the cessation of this noise will show that thecartridge has stopped falling. The mud in the drill pipe will showpulsations also as the cartridge passes the tool joints, which ceasewhen cartridge stops and also serves as an indicator. The spring underthe thimble serves to absorb the shock of the abrupt stop and preventbreakage of the container. The string is left idle a, suficient time toallow the acid to etch the glass container, and it is then pulled fromthe hole in the regular manner. If desired the receiving member can beomitted, and the cartridge al- 5s inclination of a well, is that for theacid to etch the container, as, other than dropping in the cartridgenothing but the regular drilling operations are required. Thus a greatsaving of time is made over the older methods in which the container waslowered and raised with the sand line or a special string of pipe,either of which were special operations not connected with actualdrilling.

It will be noted that ports and passages for the circulation of fluidhave been provided, so that there is no possibility of the cartridgestopping circulation whether the pilot is in a round hole or resting onthe top of the bit. It is of vital importance to maintain circulation atall times, and while not vital it is of great advantage to not have topull a wet string.

Should it be desired to use the cartridge in drill pipe of smalldiameter, spring 29 may be replaced with a rubber sleeve, or the thimblemay be omitted entirely and a seat integral with the sub l4 used. Thedesign of the cartridge may be modified as shown in Fig. 2a. In thisform the glass container is omitted and the acid placed directly in thebore l1a, the acid used having but slight action as metal. A glass rodor tube 35 is placed in a suitable opening in the body, and the boreclosed with a plug 36 which has a similar opening to receive the top ofthe rod, cushions 31 of rubber or other material being inserted. The rodwill be etched by the acid to indicate the inclination from the verticalin the same way as the bottle.

What I claim is;

1. A device as described comprising a holder having an intermediateshoulder thereon and arranged to contain an instrument capable ofrecording its position with respect to the vertical, said holder beingadapted to fall by gravity through a string of pipe, an abutment in saidstring of pipe adapted to register with said shoulder and yielding meansinterposed between said shoulder and abutment to yieldingly arrest thefall of said holder.

2. A device as described comprising a holder with a shoulder thereon andarranged to contain an instrument capable of recording its position withrespect to the vertical, said holder being adapted to fall by gravitythrough a string ofpipe, and an abutment yieldingly supported in saidstring of pipe adaptedto engage said shoulder, and thereby arrest thefall of said holder.

3. A device as described comprising a holder with a shoulder thereon andarranged to contain an instrument capable of recording its position withrespect to the vertical, said holder being adapted to fall by gravitythrough a string of pipe, a sub secured in said string at apredetermined depth, a shoulder in said sub, an abutment yieldinglysupported on said shoulder and adapted to engage the shoulder on saidholder, and thereby arrest the fall of said-holder and support it atsaid predetermined depth.

4. A device as described comprising a holder with a shoulder thereon andarranged to contain mined depth, an annular shoulder in said sub, I

an abutment having spring means yieldingly supporting it on said annularshoulder and adapted to engage the shoulder on said holder, and therebyarrest the fall of said holder and support it at said predetermineddepth.

5. A device as described comprising a tubular holder formed with aconical portion at its lower end to serve as a guide and a head at itsupper end with a chamber arranged to contain an instrument capable ofrecording its position with respect to the vertical, a closure for saidchamber, an annular shoulder on said holder, said holder being adaptedto fall by gravity through a string of pipe, a sub secured in saidstring of pipe with a bore having a shoulder therein, a thimble havingspring means resiliently supporting it on said shoulder and adapted toengage the shoulder on said holder and thereby arrest the fall of theholder.

6. The combination of a string of pipe including a member with asubstantially cylindrical bore of reduced diameter, a holder having acylindrical portion of diameter corresponding to the reduced bore ofsaid member and having an outstanding shoulder, said holder beinginsertable into said bore from one end to insure axial alinementtherewith, said member having an outstanding-seating ledge at one endfor coaction with said shoulder, an instrument in said holder capable ofrecording its position with respect to the vertical, and cushioningmeans supporting said container in said holder.

'7. The combination of a string of pipe includ- I ing a member with asubstantially cylindrical bore of reduced diameter, a holder having anoutstanding shoulder and a cylindrical portion with a pointed end, thecylindrical end being of a diameter corresponding to said reduced boreand insertable into said bore to insure axial alinement therewith, andsaid pointed portion acting as a pilot guide to register said holderwith the bore of said member, said member having an outstanding seatingledge at one end for coaction with said shoulder, an instrument in saidholder capable of recording its position with respect to the vertical,and cushioning means supporting said container in said holder.

8. The combination of a string of pipe having a sub with a cylindricalbore of reduced diameter interposed in said string, said sub having ashoulder at the upper end, a free falling holder having a cylindricalportion of a diameter cor--, responding to said bore with an outstandingshoulder for seating on the shoulder of said sub whereby the fall ofsaid holder will be arrested and said holder supported by said sub inaxial alinement therewith, said sub having a pointed end to pilot itinto said bore, an instrument capable of recording its position withrespect to the vertical, and cushioning means supportln said containerin said holder] 9. The combination of a string of pipe having a sub witha cylindrical bore of reduced diameter interposed in said string, thewall of said bore being fluted to by-pass liquid, a 'free falling holderhaving a cylindrical portion of a diameter corresponding to said borewith an outstanding shoulder for seating on said sub whereby the fall ofsaid holder will be arrested and said holder will be supported by and inaxial alinement with said sub, an instrument capable of recording itsposition with respect to the vertical, and cushioning means supportingsaid container in said holder. 10. The combination of a string of pipehaving a sub with a cylindrical bore of reduced diameter interposed in.said string, the wall of said bore being fluted to by-pass liquid, saidsub having a. shoulder at its upper end, a free falling holder having acylindrical portion of a diameter corresponding to said bore with anoutstanding shoulder for seating on the shoulder of said sub whereby thefall of said holder will be arrested and said holder will be supportedby said sub in axial alinement therewith, said sub having a pointed endto pilot it into said bore, an instrument capable of recording itsposition with respect to the vertical, and cushioning means supportingsaid container in said holder.

HARRY H. JONES.

